Oil well jet propulsion unit



Jan. 11, 1955 w. SCOTT OIL WELL JET PROPULSION UNIT 2 Sheets-Sheet 1 Filed Dec. 12, 1949 I snveni'or hz/kr jcof) MS WM Jan. 11, 1955 w. soon" on. WELL ,JET PROPULSION UNIT 2 Sheets-Sh ee t 2 LII-r Filed Dec. 12, 1949 A TTGR/VEY United States Patent OIL WELL JET PROPULSION UNIT Walter Scott, Vancouver, British Columbia, Canada Application December 12, 1949, Serial No. 132,578

1 Claim. (Cl. 103-260) This invention relates to an oil well jet propulsion unit, the object of which is to provide efficient means that will recover the oil from a well more profitably, particularly from wells which are naturally non-productive due to insufficient subterranean pressure to lift the oil to the surface, and in a well which needs some form of generated pressure or pressure from some outside source.

The jet part of my invention is inserted into the well casing to increase the rate of flow of the oil from the well as delivered at the surface.

The advantage in my invention in comparison with conventional oil recovery methods is that it dispenses with expensive slow speed piston type pumps usually installed in connection with oil extraction from wells when there is not sufficient natural pressure, which pumps require constant servicing due to the variability in the viscosity of the oils on account of varying climatic conditions- A low pressure type compressor is required with this unit to keep the jet supplied with fuel under a correctly regulated pressure indirectly to the jet element of the unit.

Advantage is taken of the adaptation of a venturi outlet tube from the jet unit to increase the velocity at the jet outlet by choking by means of tube constriction immediately before the expulsion outlet aperture of the jet chamber is reached by the combusted gas, thus creating low pressure in the area about the annular constricted portion of the venturi tube, and in the form of an injector nozzle. This results in a high velocity of oil being maintained in what may be best described as the production tubing within the well for carrying the oil to the surface.

Further advantage in the use of this jet propulsion unit is that it is a more economical method of oil extraction than other conventional methods, and that it increases production from a well, since the oil flows more readily on account of the higher viscosity of the oil due to the increased temperature resulting from the continuously ignited jetted gas, and also from the high velocity of the production.

A still further advantage resides in the fact that there is found to be extreme flexibility and controllability in such a method of oil production at all times at ground level, coupled with a minimum of maintenance expenses as compared with other methods using applied pressure, and in cases where there is no natural pressure source available this unit should prove of very great value in the industry.

Temperature indicators, in the form of thermo couples, are installed in the bottom of the well, as well as thermo couples within a pre-expansion gas chamber, which chamber is for the electrical ignition of the gas, as later described in detail.

By the use of this unit increased production is a resultant of the novel and etficient means adopted of forcing heat into the well, together with the effects of the high expulsion pressurized gas developed within the preexpansion chamber The adoption of this jet propulsion unit with its method of oil extraction will eliminate any objection to and deterrent effect of waxing and the collection and accumulation of congealed sediment at the bottom of a well.

The amount of gas required to provide the propulsive effect in this jet method of oil extraction, especially in deep wells, is found to be only a fraction of that required for use by ordinary gas operated lift means as performed by pumps for generating the required pressure. Such economy in oil production should prove of considerable importance in any gas conservation system. Fire hazard at the well head is practically an impossibility as there 1s not any oxygen admitted down the well for the functioning of the unit.

By preference the power supply equipment would consist of a standard type internal combustion engine to drive a standard type compressor of single stage and slow speed, suitable for supplying the required amount of compressed air to the aforementioned pre-expansion chamber. As a matter of safety pressure indicating apparatus would have to be installed.

A chambered back-flash preventor device is installed serially in the jet propulsion system between the compressed air pipe and the pre-expansion chamber, having gauze screens as a preventive against ignition of accumulated gases. This device is to be made of material which will withstand high temperatures, from zero to possibly 600 degrees F.

With this unit installed in the bottom of a well all the requisite adjustments are made at the surface without withdrawing any part of the apparatus below or disturbing same.

The basis of my invention is the application of a jet propulsion means for raising oil from a well by the introduction of heat and pressure therein, and/or for increasing the flow of oil therefrom.

This invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications do not indicate any material departure from the salient features of the invention as expressed in the appended claim.

Fig. 1 is a general elevational view typifying the ap paratus on the surface, with an enlarged partly sectionalized portion of the well and casing, with the nozzle and pressure chamber in place.

Fig. 2 is an enlarged detail of the pressure chamber and ejector nozzle, partly sectionalized.

Fig. 3 is a plan view of Fig. 2

Fig. 4 is a partly sectionalized view of the pre-expansion chamber.

Fig. 5 is a partly sectionalized view of the back-flash preventor device.

Fig. 6 is a cross sectional view on line 66 in Fig. 4.

Fig. 7 is a cross sectional view on line 7--7 of Fig. 5.

With reference to the drawings the numeral 1 refers to a well easing, into which a jet unit A is lowered from the surface. Between this unit and the said casing are pressure guide springs 2 attached to the outer face of the case 3 of the unit A, and they press slidably against the casing 1. This unit A is supported on a pedestal 4 screwably connected to the circular bottom plate 5 of the unit, this pedestal resting on the bottom of the drill hole.

The unit A comprises a chamber 6 within the said case 3, which chamber is enclosed also between the bottom plate 5 and a top cap 7, and is thus completely closed with the exception of two circular apertures, one for the insertion of a pressure tube 8, and the other for the insertion of a piece of tubing 9. The tube 8 leads down from the surface for the conveyance of high pressure gas in a continuous flow as later enlarged upon in this description. The tube 9 contains a ball valve of the check valve type with a contained ball 10 on a seat 11, the ball being so seated as to allow an outflow from the chamber 6, and to check back pressure into the chamber.

A cone shaped injector type nozzle 12 forms a choking passageway for outflowing heated gas from the chamber 6 by way of the valve, and it is exterior to the plate 7, the upper end of said nozzle being truncated, as illustrated in Fig. 2, to form a restricted aperture 13. The nozzle is axially aligned with a production tube 14 rising the full height of the well casing and above it, and it is welded to the top plate 7. Immediately surrounding the nozzle the cross sectional area within this production tube is reduced gradually towards the aperture 13 at the apex of the nozzle, and is increased above and below the aperture to the full diameter of the tube. This provides an annular space around the nozzle gradually restricted in area towards the aperture thereof to generate a Wenturi tube effect on the conventional injector principle.

Ports are disposed around the bottom of the production tube 14 for the outflow passage of accumulated oil from the well casing under high velocity as an effect of the venturi tube, which increase in velocity is sufficient to raise the oil to the storage equipment above ground level, the pressure originally being generated, as hereinafter described, for this purpose.

A thermo couple 16 is installed within the chamber 6 which couple is connected up to the surface by a cable 16a and is press-sealed through the cap 7. Temperature recordings with variations thereof may thus be observed above ground.

The unit A is equipped with a pair of clevis members 17 for convenience in lowering it and raising it into and out of the casing by cable.

The pressure generating apparatus at the surface comprises a pre-expansion chamber 18 connected directly on to the open end of the pressure tube 8, and is connected in series with a back-flash preventor unit 19, and at its opposite end. A comparatively slow speed air compressor B supplies the necessary high pressure air through the said back-flash unit 19 and into the said pre-expansion chamber 18. Oil is supplied for combustion into the latter chamber through a series of oil nozzles 20 from an oil pump 21 operated by a pulley on the rotatable shaft of the said compressor, which shaft 22 is rotated by pulley and belt connection with a motor driven pulley 23. A motor 24 is installed for driving the compressor, and may be of any conventional type. The pump 21 is supplied with oil from any convenient outside source of oil storage.

In the pre-expansion chamber 18 the mixed fuel and air are ignited by means of a series of spark plugs 25 axially offset relatively with the oil nozzles 20, and are connected to a source of electrical energy not shown. In operation the combustion takes place continuously within this chamber 18, and the gases are forced through its outlet end 26 at high pressure, the flow being checked at its intake end 27 by means of a spring valve 28 closing on a seat 29. A spring 30 assures the proper closing of this valve if and when necessary. It is from this chamber 18 that the oil lift in the well is started and maintained, the velocity of the continuously combusted gases therefrom being augmented by the injector nozzle 12 as previously described. There are some thermo couples 30a installed in the chamber 18 for checking on the high temperature therewithin.

The back-flash preventor chamber 19 is divided partitionally into compartments by a series of fine gauze screens 31 spaced equally apart therein. These screens prevent any possibility of flame transmission in a reverse direction from the chamber 18 to the compressor line, to which the preventor chamber is directly connected.

A natural gas tank 32 is shown merely to complete the unitary operational features of this apparatus from the source of power needed to attain the specific result of oil extraction from a well.

The expansion chamber temperatures may range from zero to 3000 degrees F. Any valvular failure would at once be indicated by a pressure gauge in air line 33 shown at 33a. A relief valve 34 is also installed in this air line.

The screens 31 are secured in place by spacer rings 35, and are disposed within the larger chambered portion of this chamber 19 of the flash preventor, which chamber terminates at each of its ends with exteriorly threaded pipe connection tubes 36 and 36a.

Oil feed pipes 37 lead from the oil pump 21 to each individual oil nozzle 20 in the chamber 18. The intake end of this chamber 18 is fitted with a screwed head piece 38 for coupling with the back-flash preventor 19, and it contains the valve 28, the stern of which shown at 28a is slidable in a bushing 39 supported by cross arms 40, leaving clearances therebetween for the passage of the compressed air. A screwed head piece 41 at the opposite end of this pre-expansion chamber couples it with the pressure tube 8.

In the ball valve within the jet unit A the ball travel is lghecked by means of a stop pin 42 inserted across the tu e 9.

The restriction mentioned at the outlet end in the pre-expansion chamber 18 is the inserted pipe connection with the pressure tube 8.

I claim:

Oil lifting apparatus for non-self-ejecting oil wells comprising in combination with a pressurized fuel source, means forming a substantially cylindrical ignition chamber having a series of fuel supply intake nozzles therein and connected to said fuel source, means for detonating fuel in said ignition chamber, means forming a substantially cylindrical enclosed propulsion chamber adapted to be situated within an oil well, a conductor tube communicating between said ignition chamber and said propulsion chamber and a production tube communicating between said propulsion chamber and a storage tank, said ignition chamber adapted to produce a substantially continuous high pressure region in said conductor tube, a pressure jet providing communication between the production tube and the propulsion chamber and extending into the production tube, a check valve means depending from said pressure jet and positioned in said propulsion chamber whereby back flow through the jet is prevented, said pressure jet having a restricted discharge orifice, at least one oil intake port in the wall of said production tube adjacent the pressure jet, and a venturi throat in said production tube surrounding said pressure jet and positioned above said intake port.

References Cited in the file of this patent UNITED STATES PATENTS 52,721 Lansdell Feb. 20, 1866 265,246 Conord Oct. 3, 1882 519,728 McGowan May 15, 1894 798,347 Kamish Aug. 29, 1905 916,366 Plimpton Mar. 23, 1909 973,351 Hoffman Oct. 18, 1910 1,343,693 Thomas June 15, 1920 1,758,346 Arutunolf May 13, 1930 1,763,030 Wolfe June 10, 1930 2,532,635 Miller Dec. 5, 1950 

